Polymeric products of b10h10= and b12h12=-containing compounds



United States Patent 3,441,389 POLYMERIC PRODUCTS OF B H AND B H CONTAINING COMPOUNDS Seymour Yolles, Newark, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 455,949, May 14, 1965. This application Apr. 9, 1968, Ser. No. 719,852

Int. Cl. Clllb 6/20, 21/06 US. Cl. 23-358 12 Claims ABSTRACT OF THE DISCLOSURE Polymers having structural formula characterized by at least one of the repeating units r 1 .r l Tiilifil Li 11 5111.

where A is nitrogen or phosphorus; R is hydrogen or C -C alkyl and n is 250; and hydrolyzates thereof.

l, ,l and L LR RAHLL R RAKE-In Formula I Formula II where A is nitrogen or phosphorus, R is hydrogen or C C alkyl, and n is a positive integer in the range from about 2 to 50, and preferably from 10 to 40. For example, compounds such as (NHQ B H and (NH 13 1-1 are converted in accordance with this invention to polymers I and II, respectively, in which A is nitrogen R is hydrogen and n is 2-50. (CH NH B H and convert to polymers I and II, respectively, in which R is CH and A is nitrogen. The corresponding phosphorus compounds (CH PH B H and (CH3PH3)2B12H12 produce corresponding polymers 1 and II in which R is CH and A is phosphorus. By using mixtures of B and B boron cage compounds as starting materials, polymers are produced containing repeating units of both Formula I and Formula 11. Each of the polymers of this invention will normally be terminated with the end groups -B H -+AH or B H +AH depending upon whether :1 B or B boron cage monomer is involved.

The above polymers are prepared by heating a compound of the formula (RAH B H or at a temperature of ZOO-400 C. for several hours, usually from about 4 to 10 hours. The pressure is not critical but the reaction proceeds more rapidly at super atmospheric pressure. Atmospheric pressure is usually preferred. The reaction is practically instantaneous at 400 C. and 19,000 atmospheres and proceeds with almost explosive violence. Preferably a temperature range of 250300 C. and atmospheric pressure for a period of Patented Apr. 29, 1969 ice 4-l0 hours is utilized. These boron cage compounds, if pure, require higher reaction temperatures than impure compounds for the same reaction rates.

Hydrogen gas is evolved during the reaction and sometimes small amounts of ammonia. The latter is usually evolved along with hydrogen When an impure boron cage compound is employed. Completion of the reaction is indicated when gas ceases to evolve or, in other words, when pressure in the reaction vessel, if it is closed, becomes constant. The polymers of this invention are mostly linear and are amorphous solids, partially soluble in Water and dimethyl sulfoxide. Characterization of the structures of polymers of this invention is verified by infra-red and nuclear magnetic resonance techniques and conductometric titrations. These polymers can be hydrolyzed in water to remove NH groups; the hydrolyzate will usually contain two H O molecules per B or B boron cage unit in the polymer.

The hydrolyzate will have the structural formula:

Formula IV where A, R, and n are as defined above.

The following exemplary polymers are prepared in accordance with this invetnion from the reactants indicated:

LOH; CHsPHz Polymers of this invention are unique in having wholly inorganic backbones and containing high concentrations of boron and hydrogen atoms which have high neutron cross-sections. These polymers, therefore, are useful as neutron shielding materials and are substantially superior in performance in this respect to monomeric materials in that they can be used in the form of coatings and insoluble films which renders their application and utility more versatile than said monomeric materials. These polymers are also unique in possessing a high reducing potential which makes them suitable for use in redox ion exchange materials. Additionally due to their polymeric nature and reducing portion they are useful in batteries and fuel cells. These polymers also show good anti-static properties and can be applied to substrates calling for such properties. They can also be used as sequestering agents for heavy metals.

The following examples illustrate the invention.

Example 1 A 15.4 gm. sample of twice recrystallized was placed in a glass liner and heated at atmospheric pressure in a bomb for 8 hours at 265 C. and an additional 4 hours at 300 C. The weight loss was 0.73 g. and the eflluent gas was identified as hydrogen by the mass spectrometer. The product was identified as having the structure of Formula I where A is nitrogen and R is hydrogen. The molecular weight was about 2000.

A 12.95 gm. sample of the yellow pyrolysate was refluxed with 200 ml. of water for hour with evolution of ammonia. The solution was filtered hot and the insoluble precipitate was washed with boiling Water. The filtrate was combined with washings and the solid which separated on cooling was also filtered oif. Additional solid was obtained when the liquid volume was reduced. Finally, a solid is obtained on evaporating to dryness which is a hydrolyzate of the Formula I product and contains two molecules of water per B cage unit.

Example 2 Following the procedure of Example 1, except that (NH B H was pyrolized and the pyrolyzate recovered and analyzed. The rate of the reaction was much slower than in Example 1. The product had the structural formula of Formula II where A is nitrogen and R is hydrogen. The molecular weight was about the same as in Example 1. This polymer upon hydrolysis loses NH groups and adds two molecules of water per B -boron cage unit.

I claim:

1. A polymer having a structural formula characterized by at least one of the repeating units where A is selected from the group consisting of nitrogen and phosphorus; R is selected from the group consisting of hydrogen and C C alkyl; and n is a positive integer in the range from about 2 to 50.

2. A polymer having the structural formula where A is selected from the group consisting of nitrogen and phosphorus; R is selected from the group consisting 4 of hydrogen and C -C alkyl; and n is a positive integer in the range from about 2 to 50.

3. The polymer of claim 2 in which A is nitrogen. 4. The polymer of claim 2 in which R is C -C alkyl. 5. The polymer of claim 4 in which R is hydrogen. 6. A polymer having the structural formula where A is selected from the group consisting of nitrogen and phosphorus; R is selected from the group consisting of hydrogen and C -C alkyl; and n is a positive integer in the range from about 2 to 50.

7. The polymer of claim 6 in which A is nitrogen.

8. The polymer of claim 6 in which R is a C -C alkyl.

9. The polymer of claim 8 in which R is hydrogen.

10. A process for producing a polymer having a structural formula characterized by at least one of the repeating units R RAH2 L R RAH- L O I Z?I0HT1 BIOHD AH4+ 2nH2O LR OH .L R

where A is selected from the group consisting of nitrogen and phosphorus; R is selected from the group consisting of hydrogen and C -C alkyl; and n is a positive integer in the range from about 2 to 50.

12. A polymeric hydrolyzate having the structural formula characterized by the formula where A is selected from the group consisting of nitrogen and phosphorus; R is selected from the group consisting of hydrogen and C -C alkyl; and n is a positive integer in the range from about 2 to 50.

References Cited UNITED STATES PATENTS 9/ 1964 Knoth 23-362 2/1965 Miller et al 23-362 OSCAR R. VERTIZ, Primary Examiner. HOKE S. MILLER, Assistant Examiner.

US. Cl. X.R. 23315, 361, 362, 

